Rust inhibited oil containing aliphaticaminoalkylsuccinates



United States Patent 6 Claims. (Cl. 44-71) This invention relates tochemical compounds and their use as rust inhibitors and corrosioninhibitors in normally liquid oleaginous compositions. This inventionfurther relates to and provides normally liquid oleaginous compositions,especially in the presence of water, inhibited against rust andcorrosion by the inclusion therein of certain hydroxyamine esters ofsuccinic acid provided herein.

This is a division of application Serial No. 106,196, filed April 2-8,1961, which issued as US. 3,123,634 on March 3, 1964, and is entitledN-Aliphatic-N,=NDi(Alkyl Monosuccinate)Amine.

In the handling and storage of many normally liquid bydrocarbons andhydrocarbon products, serious problems of corrosion are encounteredparticularly corrosion to ferrous metal parts. Under conditions ofhandling the storage of normally liquid hydrocarbons, water oftenbecomes included with the hydrocarbon through seepage, condensation oreven from processing of the hydrocarbon. Also present in the hydrocarbonin many instances are acidic and/ or caustic substances in small amountsresulting from prior treatment of the hydrocarbons, e.g. from acidtreating and/or caustic treating of fuel oils and lubricating oils. Suchacidic and/ or caustic materials are corrosive toward metal parts suchas storage tank walls, valves, pipelines, tank car walls, burners,gasoline tanks, crankcases, etc. Other corrosive substances may beformed through oxidative deterioration of the hydrocarbon in thepresence of oxygen particularly if the hydrocarbon is stored forsubstantial periods of time or stored or supported under adversely hightemperature conditions. The water present in the hydrocarbon oftencauses the formation of two Separate phases, i.e. a hydrocarbon phaseand an aqueous phase. The corrosive materials become distributedthroughout both the hydrocarbon and aqueous phases and it becomesdesirable, if not necessary, to protect against corrosion of metal partsfrom both phases. The presence of the water phase also, of course,promotes rusting of metal parts such as tank walls, pipes, etc. Thepresent invention provides normally liquid hydrocarbon compositionswhich have imparted thereto the ability to protect against rust andcorrosion of both phases by the inclusion therein of certain corrosioninhibiting agents.

The compounds of this invention have the structural formula:

wherein R is an open-chain (non-cyclic) aliphatic hydrocarbon groupcontaining from 8 to 22 carbon atoms and R and R are selected from theclass consisting of hydrogen, methyl and ethyl. R may be saturatedmono-unsatuated, di-unsaturated or poly-unsaturated, preferablysaturated, mono-unsaturated or di-unsaturated. In the preferredembodiments, R contains from 12 to 13 :arbon atoms and R and R" are eachhydrogen.

The compounds may be termed monoesters of succinic acid or diesters ofan N,N-di(hydroxyallryl)-N-aliphatic amine but are more descriptivelyreferred to herein as N-aliphatic-N,N-di(alkyl monosuccinate) amine or,more simply, as aliphaticaminoalkylsuccinates.

The aliphaticaminoalkylsuccinates may be used in accordance herewith ina normally liquid hydrocarbon'in amounts suflicient to inhibit corrosionand more desirably in amounts sufficient to inhibit corrosion caused bythe presence of water in a separate phase in contact with the normallyliquid hydrocarbon. More advantageously, the corrosion inhibitors may beused in amounts of from about 0.00005 to about 10 weight percent in anormally liquid hydrocarbon and preferably in amounts of about 0.001 toabout .01 weight percent. The salts, e.g. the amine salts and especiallythe substituted-imidazolinium salts, of thealiphaticaminoalkylsuccinates can also be prepared for use as effectivecorrosion inhibitors by reacting sufficient substituted imidazolinetherewith to neutralize one ,or both carboxylic acid groups.

The R group of the compounds apparently serves two functions. Thehydrocarbon chain provides the property of oil-solubility and alsoprovides a sufficiently thick mononuclear layer for the purpose ofprotecting metal surfaces against rust and corrosion.

More specific examples of compounds of this invention are listed below.'For simplicity in nomenclature, the listed examples are identified withreference to the structural formula set out above by identification ofthe R, R and R" groups.

Example N o. R R R Octadecyl Hy-drogen Hydrogen- Tallow d0 Methyl.

do Ethyl.

0. Hydrogen.

.do Ethyl. Docosyl Hydrogen Hexadecadienyl Ethyl. Heptadecyl 1 Methyl.Oleyl -do Hydrogen. Octyl do D0 Ethyl. Hydrogen. o.

Ethyl. Hydrogen.

The designations coco, soybean and tallow are used to designatealiphatic groups derived from coco amines, soybean amines and tallowamines respectively. The coco, soybean and tallow amines are derivedfrom the coconut fatty acids, soybean fatty acids and tallow fatty acidsby reaction of the fatty acids with ammonia resulting in the formationof mixtures of amines having varying molecular weights. The aminesprepared from the fatty acids are available commercially under the tradename Armeen. The Armeens may advantageously be used as a source ofprimary aliphatic amines in preparing N,N-di(beta-hydroxyalkyl)N-aliphatic amines for use in preparing compounds of this invention.Examples of the Armeens are Armeen T (derived from tallow fatty acidsand containing about 2 0 tetradecyl amine, 24% hexadecyl amine, 28%octadecyl amine and 46% octadecenyl amine) and Armeen 12 (containing 2%decyl amine, dodecyl amine and 3% tetradecyl amine). Other amines fromwhich the N,N-di(beta-hydroxyalkyl) -N-aliphatic amines may be derivedare the Alamines such as Alamine 26 (a mixture of saturated,mono-unsaturated and di-unsaturated C primary amines) and Alamine 21D(distilled primary coco amine).

The compounds of this invention may be conveniently prepared by reactingequirnolar amounts of the corresponding N,N-di(beta-hydroxyalkyl)N-aliphatic amine With succinic anhydride. The reaction may beconveniently carried out at normal esterification temperaturespreferably in the range of 100-200 C. or higher if desired. The reactionproceeds at a more rapid rate at higher temperates and at a slower rateat lower temperatures. The reaction is terminated, e.g. by removal ofheat upon completion of the desired esterification, 2 to 8 hours usuallybeing sufficient for completion of the reaction. Succinic acid may beused in lieu of the anhydride, if desired, but the anhydride ispreferred. Where the acid is used in lieu of the anhydride, the waterformed may be removed by distillation, but removal of water is notnecessary where the anhydride is used.

The reactions in forming the compounds useful in this invention mayconveniently be carried out using a solvent in the reaction medium.Useable solvents are the aromatic hydrocarbons and particularly thelower boiling hydrocarbons such as benzene, toluene, xylene,ethylbenzene and the like. It is usually not particularly desirable toremove the solvent after the reaction, especially where the solvent isan aromatic hydrocarbon which may be permitted to be incorporated intothe normally liquid hydrocarbon to which thealiphaticaminoalkylsuccinates are added. The lower boiling aromatichydrocarbons are preferred because they boil within the most desirablereaction temperature ranges. The solvents may function in controllingreaction temperature in that the reaction may be carried out at thereflux temperature of the solvent.

The iN,N-di(beta-hydroxyalkyl) N-aliphatic amines may be prepared by thereaction of two moles of the corresponding alkylene oxide with one moleof the corresponding primary aliphatic amine. The alkylene oxide-primaryamine reaction is well known to the art. Useable alkylene oxides, forexample, are ethylene oxide, propylene oxide, butylene oxide, etc.Examples of useable primary amines are the amines having the formula RNHwherein R is as identified above. These include, as more specificexamples,

7 all of the primary amines having R as specifically identified in thetable of examples set out above.

As a typical preparation of an aliphaticaminoalkylsuccinate, 18.60 gramsof bis-(beta-hydroxyethyl)-octadecylamine dissolved in 200 m1. ofbenzene were added slowly with stirring to 1 0.00 grams of succinicanhydride in 100 ml. of benzene. The mixture was refluxed for fourhours. The solvent was removed by vacuum distillation leaving 28 gramsof N-octadecyl-N,N-di(ethyl monosuccinate) amine, having the formula:

(I) o on oniodomomiion n ar omenzor omonn lon as a viscous liquidproduct.

The normally liquid hydrocarbons include those hydrocarbons boiling inthe gasoline through lubricating oil range and preferably those normallyliquid hydrocarbons boiling in the gasoline distillation range. Examplesof normally liquid hydrocarbons are gasoline, heater oil, jet fuel,kerosene, mineral lubricating oils, synthetic hydrocarbon lubricatingoils, furnace oils, residual heating oils, fuel oil blends containingresidual and distillate fuel oils, e.g. Bunker C, gas oils and otherresidual and distillate fuel oils. The normally liquid hydrocarbons maycontain other non-hydrocarbon components, e.g. sulfur, normally presentin diesel fuels. The lubricating oils may be sulfur extracted ifdesired. The normally liquid hydrocarbons may be virgin hydrocarbons ormay be processed, e.g, by cracking, alkylation, reforming, isomerizationand the like.

The rust inhibitors of this invention are believed to be especiallyeffective in petroleum hydrocarbons and their preferred use is incombination with normally liquid hydrocarbons boiling in the gasolinedistillation range.

In order to illustrate the rust and corrosion inhibition properties ofthe compositions of this invention, examples of compositions of thisinvention were prepared and subjected to rust and corrosion test asfollows:

Indiana Conductometric Rust Test (station) .-This test tests forcorrosion inhibition and rust inhibition properties in the presence ofcorrosive acidic and caustic substances. The test was run using thehydrocarbon phases as identified in the table below. In accordance withthe procedure of the test, samples of 0.00073 weight percent (2 poundsper thousand barrels) of N-octadecyl-N,N-di(ethyl monosuccinate) amine,the compound identified as Example 1, above, in the hydrocarbon phaseidentified in the table below were prepared. Each sample was placed withan equal volume of Water containing added caustic and/or acidicsubstances in a test tube and stirred briefly to permit the additionagent to become distributed within both the hydrocarbon and aqueousphases. An S-shaped steel test strip, having an electrical terminal ateach end of the S was immersed in the hydrocarbon phase to reachadsorption equilibrium and the electrical resistance is noted as acontrol resistance value. The steel strip was then lowered into theaqueous phase and after 24 hours the change in electrical resistance wastaken as a measure of rusting and corrosion in both the aqueous andhydrocarbon phases during the 24-hour period. A determination of rustingand corrosion inhibition was made in terms of corrosion rate measured inmils penetration per day times 10 The mils penetration per day wereconverted to percent reduction in corrosion by the following equation:

X l00=percent reduction in corrosion r =corrosion rate of steel strip infuel with inhibitor. r =corrosion rate of steel strip in fuel with noinhibitor.

The percent reduction in corrosion is reported in the following table:

Table Percent Hydrocarbon Aqueous Phase Reduction Phase in CorrosionGasoline 10- MHCL" r 96. 2 Do--- 10- MNaOH- 95. 4 D0.-- 0.1% NaOl 99. 3Do--- 0.1% NaGl plus 10- MNaOH 97. 3 Virgin Gas Oil. Deionized WaterAlone 94. 7 Do 10- MNazSOi plus 10- MNaOH 93. 8 10- MHCl- 96. 3 10-MNaOH 80. 2 0.1% NaOL. 83. 2

The data of the table indicate the ability of the compositions of thisinvention to inhibit rust and corrosion even in concentrations lowerthan .0008 weight percent. in comparison with the control (containing noadditive) the compositions of this invention demonstrated an excellentability in inhibiting rust and corrosion in both the aqueous andhydrocarbon phases in the presence of water and under caustic and acidicconditions.

It is evident from the foregoing that I have provided compounds usefulin normally liquid hydrocarbon oils f the prevention of rust and/ orcorrosion.

I claim:

1. A normally liquid hydrocarbon composition comprising a major amountof normally liquid hydrocarbon containing a minor amount, sufiicient toinhibit corrosion, of a compound having the structural formula:

wherein R is an open-chain aliphatic hydrocarbon group having 8 to 22carbon atoms and R and R" are selected from the class consisting ofhydrogen, methyl and ethyl.

2. The composition of claim 1 wherein said minor amount is in the rangeof from about 0.0001 to about 0.1 Weight percent.

3. The composition of claim 1 wherein said normally liquid hydrocarbonboils in the gasoline distillation range.

4-. As a composition of matter, a normally liquid hydrocarbon in contactwith an amount of water normally sufficient to promote corrosion ofmetal parts and containing an amount, from about 0.00005 to about 10Weight percent, sufiicient to inhibit said corrosion of the compoundhaving the structural formula:

References Cited by the Examiner UNITED STATES PATENTS 2,368,604 1/45White 4471 2,490,744 12/49 Trigg 252-392 XR 2,614,980 10/52 Lytle252-392 XR 2,638,449 5/53 White 252-392 XR 2,805,201 9/57 Fischer 252392 XR 2,977,309 3/61 Godfrey 252392 XR 3,003,960 10/61 Andress 252-393XR 3,037,051 5/62 Stromberg 44-71 XR 3,060,007 10/62 Freedman 447l XR3,095,286 6/63 Andress 4471 3,116,129 12/ 63 Udelhofen 44--71 DANIEL E.WYMAN, Primary Examiner.

1. A NORMALLY LIQUID HYDROCARBON COMPOSITION COMPRISING A MAJOR AMOUNTOF NORMALLY LIQUID HYDROCARBON CONTAINING A MINOR AMOUNT, SUFFICIENT TOINHIBIT CORROSION, OF A COMPOUND HAVING THE STRUCTURAL FORMULA: